This introductory text aims to cover the principles of biochemistry and to give the reader a command of biochemistry's basic concepts and language. New material is related to common themes and recurring motifs whenever possible. For example, new treatments of membrane excitation and transport, signal transduction, molecular immunology, muscle contraction and cell motility, and protein folding and design have been added early to the book. Discussions of the new areas of inquiry opened up by the growing partnership between biochemistry, cell biology and molecular genetics - including a chapter of reflection on molecular evolution - are featured in the last chapter of the book.